Went to the Warhammer store this afternoon, they had an interactive display set up for their new Warhammer Tone Pro paints so I decided to try it.
I focused on the figures I barely brushed the base with gray, the flamer got some black and gray with a touch of orange and yellow. The power armor was the darkest blue available and the red was the richest they had with a lighter shade as well.
Base Brushes